Many municipal, commercial, industrial and even residential processes can generate unwanted odors. For instance, municipal water reclamation facilities and sewage treatment plants, and industrial pulp mills are often significant sources of unpleasant odors. Where such facilities are located in the vicinity of residential areas, the odor problem is compounded, although workers employed at such facilities must endure associated odors wherever located.
To address this problem, it is known to supply a controlling gas into foul air volumes at such facilities. The controlling gas reacts with foul air gases to deodorize them. One particularly effective example of this is described in U.S. Pat. No. 6,076,748, the contents of which are herein incorporated by reference in their entirety. In this example, a spray of very fine water droplets containing dissolved ozone (O3) gas is injected into the foul air volume. The ozone reacts, in various forms, with the four air gases so as to oxide them, thereby eliminating the odor. In other applications, ozone is introduced directly, to the same effect, although the method described in U.S. Pat. No. 6,076,748 is believed to represent a much faster and more efficient mechanism of odor removal.
In most foul air volumes, odor production can be highly variable and unpredictable. Accordingly, it is often impractical to simply set controlling gas supply at a predetermined level or to supply the controlling gas for predetermined time periods. This type of control will typically result in either periods of insufficient controlling gas supply to effectively combat odors or excessive production of controlling gas. Currently, the most effective control of such systems is accomplished manually, based on smell. In other words, if a foul odor is prevalent, an operator raises the controlling gas supply, if the smell of ozone is prevalent, an operator lowers the controlling gas supply.